[OpenBIOS] where I'm at with the 440gx and reading nvram
Ronald G. Minnich
rminnich at lanl.gov
Mon Jan 24 16:39:28 CET 2000
440gx agpset, page 4-2 has a nice map of the memory. 4-4 shows the
extended bios at 4GB-2M. When I do this:
unsigned long l = 0xffe00000;
unsigned long flashsize = 0x200000;
void *v;
v = ioremap_nocache (l, flashsize);
if (! v) {
printk("ioremap failed\n");
return;
}
And I probe that memory I only read 0xff. Bad. It's acting like I'm
getting all 1's due to some control chip rejecting the memory cycle. I'd
be happier with a trap ...
So I check the PIIX4E manual, page 60 (section 4.1.9), it shows that
register 4f controls what happens with accesses to the high 2MB of the 4GB
region. If you set bit 2 of 4f, requests should be forwarded. This bit is
set on my machine, but no dice anyway.
Any other thoughts welcome. This is really annoying. We have to get this
working ...
ron
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